Native American cultures of the Great Lakes region, the Ohio River Valley, and the Mississippi River Valley built distinctive large mounds in the United States over a period of more than 5,000 years.
19th-century scientists theorized that Native Americans were too primitive to be associated with the mounds, suspecting instead that they belonged to a vanished culture that disappeared before the arrival of Columbus in 1492.
One of the earliest theories suggested that the mounds actually originated in the north, settled in the Americas, and migrated south, where they became the Toltecs of Tula, Mexico.
Later theories linked them to the descendants of the Israelites, the ancient Egyptians, the Welsh, the Irish, the Greeks, the Chinese, and the Phoenicians, and even crossed over into the realm of pseudoscience by suggesting a connection to the lost continent of Atlantis.
Why are mounds special?
Reasonable scientific studies have shown that mounds were built by Native American cultures between about 3500 BC and the 16th century AD, which includes part of the Archaic period (8000 to 1000 BC), the Woodland period (1000 BC to AD 1000), and the Mississippian period (800 AD to 1600 AD).
One of the earliest mound complexes was constructed at Watson Brake in Louisiana around 3500 BC during the Archaic period. The site was developed over the centuries by a pre-agricultural, pre-ceramic hunter-gatherer society that inhabited the site seasonally.
The builders constructed an arrangement of eleven earthen mounds, about 7.6 m high, connected by ridges, forming an oval-shaped complex.
Another early site is Poverty Point, a ceremonial mound and range complex on Bayou Macon, also in Louisiana. Poverty Point was built in several phases, the earliest beginning around 1800 BC during the Late Archaic period and lasting until 1200 BC.
One of the oldest mound complexes
The builders were a hunter-fisher-gatherer society known as the Poverty Point culture that inhabited much of the lower Mississippi Valley and surrounding Gulf Coast.
The ramparts consist of six concentric C-shaped mounds extending three-quarters of a mile on the outermost crest. The most prominent features on the ground are mounds constructed of a clay soil type that reach heights of up to 21.9 meters.
During the Woodland period, mound cultures existed throughout the eastern United States, reaching as far west as Crystal River, Florida. One such culture is the Adena culture in Ohio, which primarily constructed burial mounds for funerary rituals in which earth was piled directly on top of a cremated mortuary structure to form the monument.
Also in Ohio, during the Woodland period, the Hopewell culture emerged, a collection of widely scattered peoples connected by a common network of trade routes.
The burial mounds house complex burials
The people of this culture constructed complex geometric burial mounds that were used for burials and tombs in the shape of animals, birds, or coiled serpents.
Hopewell created some of the finest crafts and artwork in the Americas. Most of their works had some religious significance, and their tombs were filled with necklaces, elaborate bone or wood carvings, decorated ceremonial pottery, earplugs, and pendants.
Mound building reached a new peak during the Mississippian period. Cultures such as the Plaquemine Culture and the Mississippian Culture built gigantic platform mounds and settlements that rivaled European cities in size.
Most famous is Cahokia, a Mississippian culture center built around 1050 AD in western Illinois. Cahokia consisted of 120 earthen mounds.
Why were the mounds abandoned?
The mounds varied in size and shape from raised platforms to conical shapes and crests, the largest being Monks’ Mound, a 290-meter-long platform with raised terraces, HeritageDaily writes.
After the arrival of Europeans in the Americas, early explorers found the mound-building areas largely depopulated and the mounds largely abandoned. However, there are some accounts that describe how Native Americans built the mounds and what cultural practices they engaged in.
One of the last mound-building cultures, the Fort Ancient Culture, likely had contact with and traded with Europeans, as archeological records contain evidence of European-made goods. These artifacts include brass and steel objects, glassware, and melted or broken goods that were made into new items.
The Fort Ancient culture was largely wiped out by successive waves of disease, such as smallpox and influenza, in the 17th century, suggesting that the demographic decline of the broader mound cultures of this period was also due to diseases introduced by the first Europeans who came into contact with them.